benchmark.hh

#ifndef BENCHMARK_LOADED
#define BENCHMARK_LOADED

#include "exception.hh"
#include <fmt/core.h>
#include <fstream>
#include <iostream>
#include <nlohmann/json.hpp>
#include <string>

// Bookkeeping of test data to store data of one or more tests in a json file to
// facilitate future accounting.
//
// Usage Example 1 (single test):
// ==============================
// 1. define our test
//      eic::util::Test test1{
//        {{"name", "example_test"},
//        {"title", "Example Test"},
//        {"description", "This is an example of a test definition"},
//        {"quantity", "efficiency"},
//        {"target", "1"}}};
// 2. set pass/fail/error status and return value (in this case .99)
//      test1.pass(0.99)
// 3. write our test data to a json file
//      eic::util::write_test(test1, "test1.json");
//
// Usage Example 2 (multiple tests):
// =================================
// 1. define our tests
//      eic::util::Test test1{
//        {{"name", "example_test"},
//        {"title", "Example Test"},
//        {"description", "This is an example of a test definition"},
//        {"quantity", "efficiency"},
//        {"target", "1"}}};
//      eic::util::Test test2{
//        {{"name", "another_test"},
//        {"title", "Another example Test"},
//        {"description", "This is a second example of a test definition"},
//        {"quantity", "resolution"},
//        {"target", "3."}}};
// 2. set pass/fail/error status and return value (in this case .99)
//      test1.fail(10)
// 3. write our test data to a json file
//      eic::util::write_test({test1, test2}, "test.json");

// Namespace for utility scripts, FIXME this should be part of an independent
// library
namespace eic::util {

struct TestDefinitionError : Exception {
  TestDefinitionError(std::string_view msg)
      : Exception(msg, "test_definition_error") {}
};

// Wrapper for our test data json, with three methods to set the status
// after test completion (to pass, fail or error). The default value
// is error.
// The following fields should be defined in the definitions json
// for the test to make sense:
//  - name: unique identifier for this test
//  - title: Slightly more verbose identifier for this test
//  - description: Concise description of what is tested
//  - quantity: What quantity is tested? Unites of value/target
//  - target: Target value of <quantity> that we want to reach
//  - value: Actual value of <quantity>
//  - weight: Weight for this test (this is defaulted to 1.0 if not specified)
//  - result: pass/fail/error
struct Test {
  Test(nlohmann::json definition) : json{std::move(definition)} {
    // initialize with error (as we don't have a value yet)
    error();
    // Check that all required fields are present
    for (const auto& field : {"name", "title", "description", "quantity",
                              "target", "value", "result"}) {
      if (json.find(field) == json.end()) {
        throw TestDefinitionError{
            fmt::format("Error in test definition: field '{}' missing", field)};
      }
    }
    // Default "weight" to 1 if not set
    if (json.find("weight") == json.end()) {
      json["weight"] = 1.0;
    }
  }
  // Set this test to pass/fail/error
  void pass(double value) { update_result("pass", value); }
  void fail(double value) { update_result("fail", value); }
  void error(double value = 0) { update_result("error", value); }

  nlohmann::json json;

private:
  void update_result(std::string_view status, double value) {
    json["result"] = status;
    json["value"] = value;
  }
};

void write_test(const std::vector<Test>& data, const std::string& fname) {
  nlohmann::json test;
  for (auto& entry : data) {
    test["tests"].push_back(entry.json);
  }
  std::cout << fmt::format("Writing test data to {}\n", fname);
  std::ofstream output_file(fname);
  output_file << std::setw(4) << test << "\n";
}
void write_test(const Test& data, const std::string& fname) {
  std::vector<Test> vtd{data};
  write_test(vtd, fname);
}

} // namespace eic::util

#endif